Drilling apparatus



June 14, 1938. J. F. CHAPPELL DRILLING APPARATUS Filed May 25, 1936 5 Sheets-Sheet l M W mml W 2 Q w; i vgw M m a 4 v N cl. 7f 47 77 A 5 2 m u (1 o a K add .6 I M 5 I June 14, 1938 Y J. F. CHAPPELL DRILLING APPARATUS Filed May 25, 1936 5 Sheets-Sheet 2 H .7 m 7% A \m Q I Mh 7 1 3C m m E l 5 1 L w W N w M a IO June 14, 1938. I J CHAPPELL 2,120,240

DRILLING APPARATUS Filed May 25, 1936 3 Sheets-Sheet 3 ill Patented June 14, 1938 UNITED STATES PATENT OFFICE 13 Claims.

This invention relates to new and useful improvements in drilling apparatus.

One object of the invention is to provide an improved apparatus for the drilling and coring of oil wells.

Another object of the invention is to provide an improved drilling apparatus wherein the drill pipe forms the well casing, whereby the usual casing is eliminated.

An important object of the invention is to provide an improved apparatus for drilling wells, which is so constructed that the cutting tool may be inserted in, or removed from, the well for replacement, or other purposes, without pulling the entire length of drill pipe, whereby the time, labor and expense incidental to the removal of the drill pipe is obviated and the drilling facilitated.

. Another object of the invention is to provide drilling apparatus including a rotatable drill pipe which forms the well casing, and a drill bit having retractible cutting blades, whereby said bit may be dropped or lowered on a cable or wire line and anchored at the bottom of the pipe, with means for expanding the blades into cutting position after said bit has reached ,the bottom of the pipe; the retractibility of the blades of said bit permitting the bit to be readily inserted in, or removed from, the hole without removing the drill pipe.

A further object of the invention is to provide an improved drill bit having retractible blades pivotally secured, whereby they maybe swung outwardly into cutting position, said blades 00- acting with the drill pipe to lock the bit to the pipe, whereby rotation of the pipe will rotate the bit; the cutter blades being readily removable from the bit body, whereby they may be replaced when worn, which eliminates the necessity of replacing the entire bit body.

A particular object of the-invention is to provide an improved apparatus for coring wells, which is so constructed that a core may be taken without subjecting said core to the water pressure, the coring bit being readily removable from the well without removing the drill pipe.

Still another object of the invention is to provide an improved drilling apparatus wherein a main bit is employed at the lower end of the drill pipe, and a second smaller bit depending below the main bit, with improved means for imparting a hammering action to the smaller bit while rotating themain bit, whereby drilling in hard formations is more readily accomplished.

A still further object of the invention is to provide an improved drilling and coring apparatus, wherein all the drilling and coring bits may be lowered into, or removed from, the pipe on a wire line, or cable, and the drill pipe need never be withdrawn, said pipeserving as the well casing 5 after the well is drilled.

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood 10 from a reading of the following specification and by reference to the accompanying drawings, in which an example of the invention is shown, and wherein:

Figure 1 is a view partly in elevation and partly 15 in section of a drilling apparatus, constructed in accordance with the invention, and showing the bit blade in drilling position,

Figure 2 is an enlarged view showing the upper portion of the apparatus in elevation, with the drill pipe in section,

Figure 3 is a view partly in elevation and partly in section of the drill collar having both the inner bit and the outer bit in drilling position,

Figure 4 is a view similar to Figure 2 showing all of the parts in transverse section,

Figure 5 is a bottom view of the drill pipe with the drill bit removed,

Figure 6 is an elevation of the upper connecting collar with the drill pipe in section, said con- 30 necting collar being viewed at a right angle from the part as shown in Figure 2,

Figure '7 is a transverse, vertical, sectional view of the lower end of the drill pipe,

Figure 8 is a horizontal, cross-sectional view 35 taken on the line 8-8 of Figure 1,

Figure 9 is a horizontal, cross-sectional view taken on the line 9-9 of Figure 1,

Figure 10 is a horizontal, cross-sectional view taken on the line Ill-l0 of Figure 1, 40

Figure 10a is a horizontal, cross-sectional view taken on the line |llallla of Figure 1,

Figure 11 is a horizontal, cross-sectional viewtaken on the line ll-ll of Figure 1,

Figure 12 is a horizontal, crosssectional view taken on the line l2l2 of Figure 2,

Figure 13 is a 'view partly in elevation and partly in section of the lower drill collar which, carries the cutting blade of the outer bit, said so collar being viewed at a right angle'from that shown in Figure 3,

' Figure 14 is a'horizontal, cross-sectional view taken on the line ll-ll of Figure 13,

Figure 15 is a transverse, vertical, sectional u view of a core drill which is adapted to be substituted for the inner pilot bit, and

Figure 16 is a bottom view of the same.

In the drawings, the numeral Ill designates a tubular drill pipe which has its upper end connected to the usual square kelly or other drive member (not shown) whereby said pipe may be rotated. The pipe extends downwardly within the well bore and has a bottom drill collar Ii threaded on its lower end. The bottom drill collar is constructed to receive an outer drill bit [2 so as to impart rotation to said bit as the drill pipe and collar are rotated, as will be explained. An inner or pilot bit l3 extends downwardly through the outer bit l2 and is also connected with the drill pipe. The connection between the inner bit and the drill pipe is such that a reciprocating or vertical movement is imparted thereto, as will be explained. It will be obvious by observing Figure 1, that with such arrangement a rotation of the drill pipe l0 through the medium of the kelly (not shown), will impart rotation to the outer bit l2, and will also reciprocate the inner or pilot bit 13.

The bottom drill collar II is clearly shown in Figures 5 and 7 and this collar is provided with a bore ll, which extends substantially throughout the length thereof. The upper end of the bore is threaded at l5 so that the collar may be readily screwed onto the lower end of the drill pipe I0. Near its lower end the drill collar is provided with an internal, annular oifset or shoulder IS. The construction of the underside of said collar is important and this bottom or underside is provided with a pair of diametrically opposite notches H. The trailing side of each notch is comparatively deep so as to form a flat contact face l8 as is clearly shown in Figure 5. The forward or leading side of the notch I1 is reduced and the bottom edge of the drill collar is gradually inclined from this reduced leading side ll of one notch to the enlarged trailing side I 8 of the opposite notch. Thus, it will be seen that the bottom of the drill collar is formed with two inclines which connect or extend between the diametrically opposite notches H. To strengthen the construction, I the drill collar may be enlarged as shown at l9, these enlargements being adjacent the notches l1. Vertical slots 2. are formed internally of the lower end of the drill collar and lead from the interior of the drill collar above the shoulder IE to a point forwardly of the reduced leading face ll of each notch I1. It will be seen that when water or other drilling fluid, is introduced into the drill pipe l0 and flows downwardly within the drill collar ll,'said water or drilling fluid may flow downwardly through the vertical slots 20 whereby the water will escape at the forward edges or faces of the notches I].

As above stated, the drill collar l I supports the outer or enlarged drill bit l2 and serves to impart a rotation to this bit. The construction of this bit is clearly shown in Figures 3, 13, and 14. The bit comprises a tubular body 2| which is provided with an annular external shoulder 22 located slightly below the central portion thereof. A pair of T-shaped slots 23 are cut in the lower portion of the body 2| and are located diametrically opposite each other. The horizontal leg 24 of each T-slot is disposed slightly above the annular shoulder 22. A pair of cutting blades 25 are provided with outwardly extending arms 26 at their upper ends and each blade is arranged to be supported within the slots 23. As is clearly shown in Figure 13, the extending arms 26 on the upper end of each blade are positioned within the horizontal portion 2 of the T-slots. The body or vertical portion of the blade depends downwardly through the vertical portion of the T-slots and the length of the blade body is such that the extreme lower end of the blade extends beyond the lower end of the bit body 2!. The extended arms 26 of each blade are held within the T-slots 23 by a suitable retaining member 21, which may be fastened to the body 2! by machine screws 28. It would be possible to weld this retaining member in place.

The lower end of each blade is provided with an outwardly extended cutting member 29 (Figure 3). The particular shape of this cutting member is, of course, subject to variation and by observing Figure 14, it will be seen that the cutting members 29 of the blades extend outwardly in a radial direction from the bit body 2|. When the bit I2 is in position within the drill collar H, the cutting members 29 of each blade are arranged to engage in diametrically opposite notches l1 formed in the bottom of said collar. The top or upper edge of each cutting member 29 is inclined as shown at 30 and each notch I1 is provided with a complementary incline 3|. When the cutting blades are located within the notches, the outer and lower edges of said cutting members extend beyond the drill collar H. Therefore, when the collar is rotated in a clockwise direction, (Figure 14) it will be obvious that the trailing contact face I8 of each notch engages the side of the cutting members 29 whereby a rotation is imparted to said members. Since the cutting members extend beyond the drill collar, it will be seen that a rotation thereof will cause said members to drill the hole.

It is noted that the mounting of the blades 25 within the body 2| is such that said blades are pivotally mounted in the body at their upper .ends. Since the T-slots 23 extend entirely through the side wall of the body 2|, it is obvious that the blades may be swung to a retracted position whereby the outer surface of the cutting members 29 will swing inwardly so as to lie flush with the outer periphery of the body 2|, With such arrangement, it is obvious that the blades may be swung inwardly and the body 2!.

lowered within the drill pipe I. and drill collar II. The body may be dropped or lowered by a cable and when lowered, it will continue a downward movement until the shoulder 22 on said body strikes the internal annular shoulder IG formed within the lower end of the drill collar. When the shoulder 22 is resting upon the shoulder Ii in this manner, it will be manifest that the cutting members 29 of the blades 25 are spaced from the bottom of the drill collar and this is the initial position of the drill bit prior to the commencement of the drilling.

It is obvious that since the blades 25 arepivoted at their upper ends to the body 2| that some means must be provided for expanding or swinging the lower ends of the blades outwardly into their cutting positiom For this purpose, the inner bit [3 is provided. In order that the inner bit will perform its piloting function and particularly when the drilling is in a hard formation, it is desirable that the inner bit be non-rotatable. Also, it is desirable to impart a hammering or jarring motion to the inner bit by reciprocating the same vertically, while the outer bit 12 is rotated. The inner bit may be of any suitable construction and is provided with an upwardly extending nipple 33 at its upper end, whereby the bit may be threaded on the lower end of a tubular mandrel 34. The bit is, of course, formed with the usual vertical passages 35 whereby the drilling fluid flowing downwardly through the mandrel may flow through said passages to lubricate the cutting surface of the bit as well as to wash the cuttings upwardly in the well bore. A tubular sleeve 36 surrounds the lower end of the mandrel 34 and has its lower end resting on a shoulder 31 provided externally of the bit l3. The upper end of the sleeve is formed with an external integral collar 38 whereby an external annular shoulder 39 is formed at the upper end of the sleeve. The sleeve has an external diameter which is substantially equal to the internal diameter of the body 2| of the outer bit I2 and the lower edge of the collar 38 is adapted to rest on a shoulder 40 which is provided within the body 2| at the upper end thereof. When said collar engages the shoulder 40, it will be manifest that further downward movement of the sleeve 36 is prevented. The tubular mandrel 34 which has its lower end secured to the bit l3 extends upwardly from the sleeve 36 through the drill pipe l and has its upper end secured to an actuating means, as will be hereinafter explained. By supporting the inner bit in this manner, it will be obvious that the drill pipe J0 and outer bit l2 may be rotated without imparting rotation to the inner bit l3, since rotation of the outer bit will merely rotate the sleeve 36. The mandrel 34 which has the bit l3 attached to its lower end may undergo a vertical movement with relation to the rotating outer bit, whereby a hammering action may be imparted to the inner bit |3 while the outer bit is rotating.

From the above, it will be seen that the outer bit I2 is first lowered within the drill collar II to a position where the external shoulder 22 on the bit body 2| rests on the internal annular shoulder l6 of the drill collar. It is noted that the diameter of the bit body 2| is slightly smaller than the internal diameter of the drill collar whereby an annular space 2|a is provided between said body and the collar. After the bit has been lowered to this position, the blades 25 which are pivoted to the body are still in their retracted position, since they are hanging or suspended from their pivot point in the horizontal portion 24 of the T-slots 23. The mandrel 34, sleeve 36 and the inner bit |3 are then lowered through the drill pipe l0 and enter the tubular body 2| of the bit l2. As this occurs, the bit and sleeve serve to expand the lower end of the blades 25 and these blades are held in this expanded position so long as the inner bit remains in position within the body with the sleeve 36 extending therethrough. The downward movement of the sleeve is limited by the collar 38 on said sleeve striking the internal shoulder 40 at the upper end of the bit body 2|. The mandrel 34 is of such length that the inner bit l3 extends below the cutting members 25 of the outer bit l2, whereby said inner bit engages the formation first and acts as a pilot or guide bit to maintain the drilling of the hole in a straight line.

As before stated, it is desirable to impart a reciprocating or vertical motion to the inner bit l3 while the outer bit I2 is rotating. To accomplish this vertical movement of the inner bit, the mandrel 34 which carries said inner bit extends upwardly above the lower drill collar within the drill pipe I!) and is provided with a plurality of ratchet teeth 4| at its upper end. The bore 34' of the mandrel is reduced at its extreme upper end whereby an annular internal shoulder 42 is 52 and slots formed within the upper end of said mandrel (Figure 4). A tubular shank 43 extends downwardly through the reduced portion of the bore of the mandrel and is provided with an enlarged head 44 at its lower end, The head has a sliding fit within the bore 34' of the mandrel. 34 and it will be obvious that upward movement of the shank with relation to the mandrel is limited by the head 44 striking the internal shoulder 42 of said mandrel.

A sleeve 45 surrounds the tubular shank 43 above the upper end of the mandrel 34 and this sleeve is slidable vertically on saidshank. The sleeve is provided with ratchet teeth 46 at its lower end, which teeth are complementary to the ratchet teeth 4| at the upper end of the mandrel 34, whereby the teeth of the sleeve are arranged to engage the teeth of said mandrel.- The teeth.

46 are held in engagement with the teeth 4| by a coiled spring 41 which surrounds the shank 43 and has its lower end engaging the upper end of the sleeve 45. The upper end of the spring 41 engages the underside of a collar 48 which is threaded on the upper end of the shank 43. The collar 48 is also screwed onto the lower end of a coupling member 50 which member connects the shank 43 with the drill pipe III, as will be hereinafter explained. It will be obvious that the coiled spring 41 constantly exerts its pressure to hold the sleeve 45 downwardly on the shank 43 whereby its teeth 46 are held in constant engagement with the teeth of the mandrel 34.

For imparting motion from the shank 43 to the sleeve 45 and also for limiting the movement of said sleeve with relation to the shank, said sleeve is formed with a pair of diametrically opposite slots 5| (Figure 12), which are formed in the upper end thereof. A transverse pin or bar 52 is secured in the shank 43 and has its outer ends engaging in the slots 5| of the sleeve 45. It is obvious that this bar not only limits the movement of the shank with relation to the sleeve, but also acts to impart a rotation to the sleeve when said shank is rotated.

From the above, it will be seen that the shank 43 is connected to the drill pipe III by means of the coupling member 50 and therefore when the drill pipe is rotated to rotate the outer bit I2, as has been explained, the shank 43 is also rotated. This rotation of the shank is imparted to the sleeve 45 by means of the transverse pin The mandrel 34, which is attached to the inner or pilot bit' I 3, is of course extending through the outer bit and is stationary with relation to the rotating outer bit. Therefore, as the sleeve 45 rotates with relation to the stationary mandrel 34, the ratchet teeth 46 on said sleeve will be rotated with relation to the ratchet teeth 4| formed at the upper end of the mandrel. As the teeth 46 ride into and out of engagement with the teeth 4| upon rotation of the sleeve, it will be obvious that a cam action is had, whereby a hammering action is imparted to the mandrel 34 and inner bit l3. This ham-- mering or jarring action against the inner bit |3 forces said inner bit into the formation whereby regardless of how hard said formation is, the inner bit will efficiently guide or pilot the outer bit during the drilling operation. The stroke imparted to the inner bit may be increased or decreased by varying the tension of the spring 4! which isacting against the sleeve 45 for,

obviously as this tension is increased a greater While the drilling operation is being performed, the drilling fluid is, of course, circulated downwardly through the drill pipe Ill and flows around the outer bit |2 through the clearance space 2 |a which is formed between the: body 2| and the drill collar (Figure 3). This drilling fluid will then escape to the cutting members 28 of the outer bit through the vertical passages 2|), which are formed in said drill collar, as is clearly shown in Figure 5. At the same time, the drilling fluid will pass downwardly through the tubular shank 43 and mandrel 34, from where it will flow through the passages provided in the inner bit l3. The drilling fluid will thus serve to wash the cutting members 29 and will also keep the bit l3 clean, as well as washing the cuttings which are removed from the formation upwardly in the well bore.

Any suitable means may be: provided for connecting the shank 43 with the drill pipe .lll, but it is preferable to employ the coupling member 56 which is clearly shown in Figures 2 and 4. The coupling member is adapted to be connected to a coupling collar 53, which is connected in the drill pipe Ill. The bore 54 of the collar is preferably of the same diameter as the bore of the drill pipe and a plurality of notches 55 are cut in said collar. As is clearly shown in Figure 10a, four notches are provided but it is to be clearly understood that any desired number may be employed. The tops of the notches are beveled as shown at 56 and the wall of the bore 54 of the collar immediately above the bevel 56 is inclined as shown at 51 (Figure 4). An annular shoulder 58 is provided immediately above the notches 55 and, as shown in Figure 6, this shoulder extends between said notches.

The coupling member 50 which is arranged to be connected with the coupling collar 53 is constructed of a lower section A. and an upper section B. The lower section A comprises a cylindrical body 59 which has a depending externally threaded nipple 60 at its lower end and this nipple receives the collar 48 which is secured to the upper end of the tubular shank 43. The body 59 is provided with an axial bore 6|, which extends vertically therethrough and the. upper end of this bore is enlarged and internally threaded at 62 so as to receive the lower threaded end of a tubular shank 63. The shank 63 extends upwardly through an axial. bore 64 provided in the upper section or member B of said coupling. The upper end of the bore 64 of the section B is enlarged as shown at 65 and the shank 63 is formed with an annular head 66 which is slidable vertically within the enlarged portion 65 of said bore. It is noted that the. annular head 66 extends upwardly from the shank 63 as is clearly shown in Figure 4.

The upper end of the bore of the shank 63 is formed with an annular beveled seat 61. With the arrangement above described, it will be. seen that the lower member or section A of the coupling member 56 rigidly fastened to the upper end of the tubular shank 43. The upper member or section B of said coupling: member is slidable on the tubular shank 63 which is rigidly connected to the lower section and, therefore, the upper section is movable a limited distance with relation to said lower section. The lower end of the upper section B is provided with a plurality of vertical slots 68 which receive the upper ends of elongate vertical dogs 69, said upper ends being pivoted therein on pins 10. The lower endsof the does depend from the upper section B and engage in vertical slots I I, which are formed in the lower section A of the coupling 50. The rear face 12 of each slot is curved upwardly and the extreme lower end of the slot is formed with a shoulder 73. It is obvious that when the upper section B is moved with relation to the lower 'section A with the rear faces of the dogs 69 riding on the rear curved faces 12 of the slots in the lower section, said dogs will be expanded or retracted depending upon which way the upper section B is moved. In other words, if the lower ends of the dogs engage the upper ends of the slots 1| in the lower section A, said dogs will be retracted so that their outer edges do not extend beyond the outer periphery of the lower section. However, if the upper section B is lowered with relation to the lower section A, the rear face of the dog 69 riding on the curved rear face I2 of the slot 1|, will be expanded.

The lower end of each dog is formed with an outwardly extending lug 14 and the upper edge of this lug is inclined so as to be complementary with the upper beveled surface 56' of the notches 55 in the coupling collar 53. The outer side of each dog inclines from the upper beveled surface of the lug 14 toward the upper portion of the dog and this inclined surface is complementary to the incline 51 formed above each notch 55 within the collar 53. With such arrangement, it is obvious that when the coupling member 5|] is lowered within the drill pipe l0 and the dogs are expanded outwardly into the notches 55 of the coupling collar, a rotation of the drill pipe and collar will impart a rotation to the coupling member 50 and the shank 43 secured to its lower end. Therefore. it will be seen that the inner bit |3 carried by the lower end of the mandrel will be given a vertical reciprocating movement when the shank 43 is rotated through the medium of the ratchet teeth 4| and 46. Rotation of the outer bit l2, as has been explained, is imparted through the engagement of the cutting members 25 of the blades 25 of said outer bit with the notches formed in the lower edge or bottom of the drill collar II. In the operation of the apparatus, the outer .or large drillbit I2 is first lowered through the drill pipe and into the drill collar II at the lower end thereof. This bit may be dropped or lowered by any suitable means, as by a tool engaging an internal annular shoulder 40' which is provided at the upper end of the 'bit body 2| above the shoulder 40 for this purpose. Any suitable tool which may be suspended from av cable may be employed for engaging beneath. this shoulder.

Thus, it will be obvious that the bit l2 may be quickly and easily lowered through the drill pipe by a cable. When the bit body 2| enters the collar II, the external shoulder 22 on said body will engage the internal shoulder |6 provided at the lower end of said collar, whereby further downward movement of the body 2| is prevented. At this time, the blades 25 of the bit I2 are in their retracted position since they are hanging from their pivot point within the T-slots 23. The expansion of the blades during the lowering operation is prevented by the outer edges of the cutting members 29 of said blades engaging the inner periphery of the drill pipe l6 and the drill collar It is noted that when the shoulder |6 within the drill collar is supporting the bit body 2|, the pivot point of the blades 25 is just' above said shoulder I6. This causes the. lower ends of the blades, which have their cutting members 29 made integral therewith, to be located atsorn'e distance below the bottom of the drill collar I I. With the bit in such position, the cutting members 29 thereof are below the bottom of the collar and are not engaging the notches IT in the lower end or bot-- tom of said collar and, therefore, if the drill pipe I is rotated at this time no motion is imparted to the bit l2.

After the bit l2 has been lowered within the collar, as above explained, the inner bit 13 which is carried by the mandrel 34 and which has the coupling member- 50 secured to its upper end is lowered within the drill pipe. This lowering operation may be accomplished by dropping or by the same tool by which the bit l2 has been lowered, since the coupling member 50 is provided with a shoulder 50 at its upper end, which shoulder is similar to the shoulder 40' within the bit body 2|, whereby the same tool may be employed for lowering both bits. Thus, a cable can be employed for lowering the inner bit l3. As the inner bit and its mandrel 34 and sleeve 38 enter the bore of the bit body 2|, they act to expand the blades 25 of the outer bit l2. It is noted that this expansion takes place at a point below the bottom of the drill collar ll because the inner bit is supported on the annular shoulder l6 of said collar at this time. The mandrel and inner bit continue their downward movement until the collar 38 on the sleeve 36 engages the shoulder 40 within the bit body 2|.

During the time that the mandrel 34 and bit l3 are moving downwardly through the body 2|, the coupling member 50 has moved downwardly through the drill pipe 10 because it is fastened to the upper end of the tubular shank 43 which is connected to the mandrel 34. It is pointed out that since the tool (not shown) by which the mandrel is lowered, is secured to the upper section B of the coupling member 50, this upper section will be separated as far as possible from the lower section A. This is true because the weight of the mandrel and bit I3, which are secured to the lower section A of the coupling member, will pull the shank 63 downwardly until the head 66 of said shank rests on the shoulder 65 formed between the bore 64 and the enlarged portion of said bore 65 of the upper section B. Thus it will be seen that the lower section A which carries the mandrel 34 is suspended from the upper section B during the lowering operation. At this time the lugs 14, formed on the lower ends of the dogs 69 which are carried by the upper section B,

.are located at the upper end of the slots H in the lower section A, whereby said lugs are in their retracted position which permits them to clear the wall or the interior of the drill pipe Hi. Therefore, so long as the lowering operation of the inner bit [3 and mandrel 34, together with the coupling 50 at the upper end thereof, continues the dogs 69 are in their retracted position.

The coupling member 50 is so located with relation to the inner bit I3 and the coupling collar 53 is so mounted within the drill pipe ID, that when the collar 38 on the sleeve 36 strikes the shoulder 40 within the bit body 2|, the coupling member has moved downwardly beyond the coupling collar 53. Therefore, when the inner bit [3 is first lowered into the drill pipe and within the outer bit l2 to expand the blades thereof, the lugs 14 of the pivoted dogs 69 have moved downwardly below the notches 55 which are formed in the coupling collar 53. At this time a rotation of the drill pipe would not impart a rotation to the coupling member 50 and the shank 43 because the lugs 14 are not in engagement with the notches 55, and similarly no motion would be 1mparted to the outer bit I2 because the cutting members 29 of the blades 25 of this outer bit are,

not in engagement with the notches l'l formed in the lower end of the drill collar I l.

While both the inner and outer bits. [2 and I3 are being lowered into the drill pipe III, the bottom of said drill pipe is held oif the bottom of the hole. After the two bits have been positioned, they are in reality suspended from the drill collar II at the lower end of the pipe In. To establish the connection between the drill collar H and the outer bit l2 and the drill pipe I0 and the inner bit I 3, it is only necessary to lower the drill pipe from which said bits are suspended. As this lowering operation continues, the drill bit l3 will eventually strike the bottom of the hole and when this occurs, continued lowering of the .drill pipe ID will cause said pipe and the coupling collar 53 to move downwardly with relation to the sleeve 36 and the coupling member 50 carried by the mandrel. The outer drill bit l2 will move downwardly with the drill pipe until such time as this bit strikes the bottom formation and as soon as this occurs, the outer bit will become stationary. However, as soon as the inner bit I3 is stopped the lowering of the drill pipe III will cause the coupling collar 53 to move downwardly toward the lugs 14 on the outer ends of the dogs 69. The dogs are, of course, engaging the inner wall of the drill pipe just below the coupling collar because the weight of the upper section B of the coupling 50 is tending to force the dogs downwardly in the slots 68 so that the curved faces of said slots are tending to expand the lower end of the dogs at all times.

As soon as the drill pipe has been lowered a sufficient distance to permit the notches 55 in the collar 53 to move opposite the lugs 14 of the dogs 69, it will be obvious that said lugs will immediately engage in said slots. In the event that the lugs are not in vertical alinement with the notches 55, it will be obvious that the shoulder 58 which is located between each of the notches 55 would strike the upper ends of the lugs 14 and would halt any further downward movement of the drill pipe because said pipe would be suspended from the, lugs engaging under said shoulder. When this occurs, it is only necessary to rotate the drill pipe l0 slightly in either direction so that the notches 55 are vertically alined with the lugs 14. Thus, it will be seen that the provision of the shoulder 58 provides a positive means for finding the notches 55 with the lugs I4. As soon as the lugs are expanded into the notches 55 the weight 4 of the drill pipe is resting on the beveled upper edge of the lugs 14. The expansion of the dogs 69 is limited by the inclined face of each dog engaging the inclined surface 5'! which is formed above each notch 55 within the collar 53.

- As is clearly shown in Figure 4, when the dogs 69 are expanded, the inner bottom edge of said dogs is resting on the shoulders 13, which are formed at the ldwer ends of the vertical slots H in the lower section A of the coupling member. In this way, the weight of the drill pipe III which is suspended on the beveled upper edge of the lugs 14 is transferred through the lugs to the shoulders 13. Therefore, the entireweight of the drill pipe is not carried by the pins on which the dogs 69 are pivoted, but is transmitted to the coupling member 50, which is carried by the upper end of the shank 43, whereby the entire weight of the drill pipe is carried on both the inner bit and the outer bit. By the time the drill pipe Ill and drill collar II have moved downwardly a sufficient distance to permit the engagement of the lugs 14 in their respective notches 55, the drill collar II has moved downwardly with relation to the outer bit l2, which has been held stationary because of its engagement with the formation. As the underside of the drill collar ll moves downwardly, it will strike the upper in-,

clined edge 3| of the cutting members 29 of the blades of the outer bit 12. If the notches I! in the lower edge of said collar are vertically alined with the cutting members 29, said cutting members will enter said notches, as has been explained. However, in the event that the cutting members are not vertically alined with the notches, the upper edge of said members will strike the inclined bottom surface or edge of the collar II. A rotation of the drill pipe l and collar II will immediately cause the blades to ride into their respective slots.

After the parts have moved to these positions, it will be obvious that continued rotation of the drill pipe ID will impart a rotation to the outer bit l2. At the same time, the shank 43 will be rotated by means of the coupling member 50 and rotation of said shank will impart a vertical hammering or reciprocating motion to the inner bit l3. The inner bit may thus move through very hard formation and will serve to pilot the outer bit l2 during the drilling operation.

When it is desired to remove the bit for any purpose whatever, it is only necessary to lower a suitable tool (not shown) which will engage beneath the shoulder 50' in the upper end of the coupling member 50. When this is done the drill pipe 10 is then raised a slight distance so as to relieve the lugs 14 on the expanded dogs 59 of the weight of the drill pipe. This causes the lugs to move downwardly within the slots H and an upward pull on the upper section B of the coupling member will immediately cause the dogs 59 to be retracted along the inner curved faces 12 of the slots H in the lower section A of said member. It is noted that the upward raising of the drill pipe will cause the bottom of the notches 55 to strike the inclined underside of the lugs 14 and due to this inclined surface will tend to help move said lugs inwardly within their slots 68 and H. Thus it will be seen that the coupling member 50, shank 43, mandrel 34 and inner bit I3 may be readily removed from the drill pipe. After such removal of these parts, the tool may again be lowered and engage with the internal shoulder 4|! at the upper end of the bit body 2|, whereby said body may be withdrawn from its position at the lower end of the drill pipe within the drill collar II.

From the above, it will be seen that a drilling apparatus is provided wherein the drill bit is readily removable from or insertable within the drill pipe. It is never necessary to remove the drill pipe from the well in order to replace or change the bit and this results in an enormous saving of time and labor, as well as expense. After the well is drilled in the drill pipe Ill may take the place of the usual well casing and by utilizing the drill pipe as the casing expense, time and trouble are saved.

In some instances, it might be desirable to take a core of the formation while the drilling operation is being performed and to accomplish this purpose a core bit 15 may be substituted for the inner bit l3. Asclearly shown in Figures 15 and 16, the bit 15 is provided with a threaded nipple 16 at its upper end which ,is arrange to be screwed into the lower end of the mandrel 34. The bit is provided with a bore 15' which has substantially the same diameter as the bore of the mandrel. Suitable cutting teeth T! are provided at the lower end of the bit 15. When 5 it is desired to take a core, it is only necessaryto remove the coupling 50, mandrel 34 and bit l3 from within the drill pipe. These parts are, of course, connected together as has been described and are pulled to the surface of the well.

At the surface, the inner bit 13 is removed from the mandrel 34 and the core bit I5 is substituted therefor. The parts are then returned to their original position within the drill pipe with the coupling 50 connected through the keys or dogs 15 59 with the collar 53. The bit 15, of course, ex-, tends below the cutting members 29 of the outer bit blades 25. After the parts are in this position a ball (not shown) is dropped downwardly through the drill pipe and enters the upper section B of the coupling 50 and finally comes to rest on the annular seat 61 provided at the upper end of the bore of the tubular shank 63. When the ball is so seated, it will be obvious that the water or other drilling fluid which is pumped prevent the drilling fluid or water from passing downwardly around the coupling and into the bottom drill collar II from which it escapes through the slots 20 to the forward portion of the outer cutting blades 25 of the bit l2.

Rotation of the drill pipe will, of course, im- 35 part a reciprocating or hammering motion to the core bit 15, with a rotation to the outer bit I2. The ball prevents the fluid pressure from acting against the core which is being taken and, therefore, it will be obvious that the core will move upwardly into the mandrel 34 as the drilling continues. Suitable spring fingers 19 (Figure 15) may be located in the lower end of the mandrel 34 when a core is being taken, whereby after the core passes upwardly into the mandrel, said fingers will serve to hold the same therein. With this arrangement, the same apparatus shown in Figures 1 to 14 may be utilized for taking the core by merely substituting the 0 l3, mandrel 34 and coupling 54, which must be 56 lifted to the surface in order to permit the substitution of the core bit I5 for the inner'bit I3.

What I claim and desire to secure by Letters Patent, is:

1. A drilling apparatus including, a rotatable w drill pipe, means for rotating said pipe, an outer drill bit having expansible blades adapted to be lowered through the pipe to the bottom thereof, means at the lower end of the pipe for supporting the bit at the bottom of the pipe, a mandrel adapted to be inserted within the outer drill bit for expanding and holding in their expanded positions the blades of said bits, an inner pilot carried by the lower end of the mandrel and projecting below the outer bit, means for connecting the outer bit with the drill pipe whereby rotation of said drill pipe will rotate the outer bit, means for imparting a hammering motion to the inner bit, and means for connecting the last named means with the drill pipe, whereby rotation of the drill pipe will impart a hammering action to the inner drill bit.

2. A drilling apparatus including, a rotatable drill pipe, means for rotating said pipe, an outer drill bit having expansible blades adapted to be lowered through the pipe to the bottom thereof, means within the lower end of the pipe for supporting the bit at the bottom of the pipe, a tubular mandrel adapted to be inserted within the outer drill bit for expanding the blades of said bit into cutting position, an inner tubular core bit carried by the lower end of the mandrel and projecting below the outer bit, means for connecting the outer bit with the drill pipe for imparting rotation to said bit when the pipe is rotated, means for imparting a reciprocating motion to the inner bit whereby the'inner bit is driven into the formation, and means for connecting the last named means with the drill pipe whereby rotation of the drill pipe will operate said last named means to impart a hammering action to the inner bit whereby a core is forced upwardly through the core bit and into the mandrel.

3. A drilling apparatus including, a rotatable drill pipe, means for rotating said pipe, an outer drill bit having expansible blades adapted to be lowered through the pipe to the bottom thereof, means within the lower end of the pipe for supporting the bit at the bottom of the pipe, a tubular mandrel adapted to be inserted within the outer drill bit for expanding the blades of said bit into cutting position, an inner tubular core bit carried by the lower end of the mandrel and projecting below the outer bit, means for connecting the outer bit with the drill pipe for imparting rotation to said bit when the pipe is rotated, means for imparting a reciprocating motion to the inner bit whereby the inner bit is driven into the formation, means for connecting the last named means with the drill pipe whereby rotation of the drill pipe will operate said last named means to impart a hammering action to the inner bit whereby a core is forced upwardly through the core bit and into the mandrel, and means for conducting drilling fiuid downwardly through the drill pipe and directing said fluid to the blades of the outer bit during the drilling operation.

4. A drilling apparatus including, a rotatable drill pipe, an outer drill bit adapted to be lowered through the pipe to the bottom thereof and having blades arranged to be expanded into cutting position when the bit reaches the bottom or the hole, an inner bit adapted to be lowered through the outer bit, and means for imparting a hammering motion to the inner bit when the outer; bit is rotated. l

5. A drilling apparatus including, a rotatable drill pipe, an outer drill bit adapted to be lowered through the pipe to the bottom thereof and having blades arranged to be expanded into cutting position when the bit reaches the bottom of the hole, an inner bit adapted to be lowered through the outer bit and projecting below the outer bit, means for imparting a hammering motion to the inner bit when the outer bit is rotated, means for rotating the drill pipe to rotate the outer bit, and means forconnecting said drill pipe to the means for imparting the hammering to theinner bit, whereby the latter is operated when the outer bit is rotated.

6. A drilling apparatus including, a rotatable drill pipe, an outer drill bit adapted to be lowered through the pipe to the bottom thereof and having blades arranged to be expanded into cutting position when the bit reaches the bottom of the hole, an inner bit adapted to be lowered through the outer bit and projecting below the outer bit, said inner bit acting to hold the blades of the outer bit in an expanded position, and means for imparting a hammering motion to the inner bit when the outer bit is rotated.

'7. A drilling apparatus including, a rotatable drill pipe, a drill collar having notches in its lower edge portion secured on the lower end of the pipe, an outer drill bit adapted to be lowered through the pipe to the bottom thereof and having blades arranged to be expanded into the notches of the drill collar to connect said bit with the drill pipe, whereby rotation of the pipe rotates the bit, an inner bit adapted to be lowered through the outer bit and projecting therebelow, rotatable means for imparting a hammering motion to the inner bit, and a coupling for connecting said rotatable means with the drill pipe whereby the inner bit is reciprocated while the outer bit is rotating.

8. A drilling apparatus including, a rotatable drill pipe, a drill collar having notches in its lower edge portion secured on the lower end of the pipe, an outer drill bit adapted to be lowered through the pipe to the bottom thereof and having blades arranged to be expanded into the notches of the drill collar to connect said bit with the drill pipe, whereby rotation of the pipe rotates the bit, an inner bit adapted to be lowered through the outer bit and projecting therebelow, rotatable means lowered therewith into the drill pipe for imparting a hammering motion to said inner bit, and a coupling on the upper end of said rotatable means adapted to be connected with the drill pipe, whereby rotation of said drill pipe rotates the outer bit and imparts a hammering motion to connected with the inner bit and adapted to be the inner bit, the coupling being removably connected with the drill pipe to permit the removal of the inner bit and its associated parts at any time.

9. A drilling apparatus including, a rotatable drill pipe, a drill collar having notches in its lower edge portion secured on the lower end of the pipe, an outer drill bit adapted to be lowered through the pipe to the bottom thereof and having blades arranged to be expanded into the notches of the drill collar to connect said bit with the drill pipe, whereby rotation of the pipe rotates the hit, an inner bit adapted to be lowered through the outer bit and projecting therebelow, rotatable means connected with the inner bit and adapted to be lowered therewith into the drill pipe for imparting a hammering motion to the inner bit, a second drill collar in the drill pipe, and a coupling carried by the rotatable means and having expansible dogs for engaging said second drill collar to connect the rotatable means with the drill pipe, whereby rotation of said pipe imparts a hammering motion to the inner bit while rotating the outer bit.

10, A drilling apparatus including, a. rotatable drill pipe, an outer drill bit adapted to be lowered through the pipe to the bottom thereof and having blades arranged to be expanded into cutting position when the bit reaches the bottom of the hole, an inner bit adapted to be lowered through the outer bit and projecting therebelow, rotatable means connected with the inner bit and adapted to be lowered therewith into the drillthe drill pipe, whereby rotation of said drill pipe rotates the outer bit and imparts: a hammering motion to the inner bit, the coupling being re movably connected with the drill pipe to permit the removal of the inner bit and its associate parts at any time.

11. A drilling apparatus including, a rotatable drill pipe, an outer drill bit adapted to be lowered through the pipe to the bottom thereof and having blades arranged to be expanded into cutting position when the bit reaches the bottom of the hole, an inner bit adapted to be lowered through the outer bit and projecting therebelow, rotatable means connected with the inner bit and adapted to-be lowered therewith into the drill pipe for imparting a hammering motion to the inner bit, a second drill collar in the drill pipe, and a coupling carried by the rotatable means and having expansible dogs for engaging said second drill collar to connect the rotatable means with the drill pipe, whereby rotation of said pipe imparts a. hammering motion to the inner bit while rotating the outer bit. 4

12. A drilling apparatus including, a rotatable drill pipe, a drill collar having notches in its lower edge portion secured on the lower end of the pipe, an outer drill bit adapted to be lowered through the pipe to the bottom thereof and having blades arranged to be expanded into the notches of the drill collar to connect said bit with the drill pipe, whe eby rotation of the pipe rotates the bit, an inner bit adapted to be lowered through the outer bit and projecting therebelow, rotatable means for imparting a hammering motion to the inner bit, a coupling for connecting said rotatable means with the drill pipe whereby the inner bit is reciprocated while the outer bit is rotating, and means for conducting drilling fluid downwardly through the drill pipe and directing said fluid to the blades of the outer bit during the drilling operation.

13. A drilling apparatus including, a rotatable drill pipe, an outer drill bit adapted to be lowered through the pipe to the bottom thereof and having blades arranged to be expanded into cutting position when the bit reaches the bottom of the hole, an inner bit adapted to be lowered through the outer bit and projecting therebelow, rotatable means connected with the inner bit and adapted to be lowered therewith into-the drill pipe for imparting a hammering motion to said inner bit, a coupling on the upper end of said rotatable means adapted to be connected with the drill pipe, whereby rotation of said drill pipe rotates the outer bit and imparts a hammering motion to the inner bit, the coupling being removably connected with the drill pipe to permit the removal of the inner bit and its associate parts at any time, and means for conducting drilling fluid downwardly through the drill pipe and directing said fluid to the blades of the outer bit during the drilling operation.

JAMES F. CHAPPELL. 

